Sepal Length feature was removed in the step-wise model:

## Call:
## multinom(formula = Species ~ Sepal.Width + Petal.Length + Petal.Width, 
##     data = iris)
## 
## Coefficients:
##            (Intercept) Sepal.Width Petal.Length Petal.Width
## versicolor    14.15646   -17.32240     14.09906   -2.695628
## virginica    -36.44078   -25.70717     21.98210   18.765796
## 
## Residual Deviance: 13.26653 
## AIC: 29.26653